Production of greases



Patented 27,

UNITED srA'rss "PATENT amass OFFICE PRODUCTION OF GREASES Arnold A. Bondi. New Orleans. La., nssilnor, by

inesne assignments, to Shell Development Company, San Fran Delaware els oo, Calif.. a corporation of No Drawing. Application October :1, 194s,

Serial No. szsass 21 Claims. (Cl. 25H!) The present invention relates to the production of sodium soap lubricating greases.

It has hitherto been proposed to saponiiy the fatty acid component of a grease-making batch with metallic sodium. but the reaction has not been carried to completion, and the resulting grease has been of poor quality and relatively unstable;

The present invention has for its primary object the production of a sodium soap lubricant grease which eliminates the disadvantages above set forth.

Another object of the present invention is the production of a sodium soap lubricant grease wherein the time of cooking of the grease is shortened while there is simultaneously produced a grease which keeps its penetration value after ,relatively long periods of milling.

A further object of the present invention is the production of a sodium soap lubricant grease where the fatty acid component of the greasemaking batch is saponliied by metallic sodium in the presence of an addition agent which facilitates the completion of the grease-making reaction, and produces a grease which is firm, stable, shows little tendency to bleed, and has the penetration properties which characterize a normalgrease as more fully hereinafter pointed out.,

i A still further object of the present invention is the production of a sodium soap lubricant gresse' wherein the saponiilabie component of the grease-making batch is saponiiled by metallic sodium in the presence of an organic addition agent which prevents the formation of shells of hard reaction product around the globules of metallic sodium formed on the heating of the sodium, said organic addition agent preferably having a labile hydroxy group attached to a secondary or tertiary carbon atom.

Another object of the present invention is the production of a grease containing a polyglycol having a molecular weight varying from about 400 to 6000, said polyglycol being preferably a polyethylene glycol. The preferred,molecular weight is about 1500. The polyethylene glycol may be defined as a dihydroxypoiyaikylene ether.

In carrying out the present invention the alkylene radical of the dlhydroxy mlyalkylene' ether may comprise 2 to 6 carbon atoms. when the i poly'alkylene glycol is used in the making of grease to promote the reaction between the metallic sodium and the fatty acid component. it should be used in amounts varying from 1% to 25%, but preferably between 1% to 15%, based on the amount of the saponifiable fatty acid component present in the grease making mixture.

It is not intended to limit the amount of polyethylene glycol that is being added to the grease to the percentages above set forth as many de-' sirable properties are conferred upon the grease when the polyalkylene giycols are present in amounts from 0.2% to 25% based on the weight of the saponlfiable matter present in the grease, or stated diii'erently, a soda base grease having valuable properties maybe produced by incorporating in the grease .02% to 1.0% of a polyslkylene glycol and preferably a, polyethylene glycol, said percentage range being taken on the weight of the soda base grease. Usually said soda base greases contain between 3% to 15% of a sodium soap which is usually derived from stearic acid or other fatty acids of between 16 and 24 carbon atoms or their giycerides.

m In accordance with one form of the present invention, the saponiileation of the saponiflable medium of the grease-making batch is eflected inthe presence of an addition agent while the batch is being heated, said addition agent com- 5 prising an organic compound containing a labile hydroxy group or groups, said addition agent functioning during the grease-making reaction to inhibit or prevent the production of hard shells of a grease-making reaction product to around the sodlumglobules. The addition agent may comprise hydrogenated sugars and their fatty acid esters, the polyethylene glycols, and blown fatty oils which contain hydroxylated fatty acid esters formed by oxidation during the blow- In one form of the invention the addition agent is selected from a hydroxy stearic acid. or a hydroxy stearic acid ester. The addition agent may be'a monohydroxy stearic acid or a monohydroxy stearic acid ester. Very satisfactory results have been obtained by using an addition agent selected irom a group consisting of 12-hydroxy stearic' the i2-hydroxy stearic acid or its ester may be ll mixed with a polyalkylene glycol, as'for example,

and after 300 strokes, 284.

polyethylene glycol having a molecular weight Varying between 400 to 6000, but preferably havins a molecular weisht of about 1500.

The lubricating grease may have incorporated therein as an addition adent polyhydroxy-stearic acids. For example, there may be added to the batch hydroxy stearic acids in which the hydroxy groups are in the 9 or 10 carbon position. The.

polyhydroxy stearicacid may be prepared by sulfonation and subsequent hydroxylation of oleic l" acid.

The present invention will be illustrated in connection with the following examples:

' Example 2 t2 grams of metallic sodium are emulsified with a small amount of lubricating'oil in any appropriate type of emulsifier. Preferably 42 grams of metallic sodium are emulsified with 100 gr oi 2000 vis. at 100 F. coastal lubricating oil at a 20 temperature of about 220 F. The amount oi metallic sodium used is the stoichiometric amount required to neutralize the fatty acid component of the hatch. A greater amount may be used it desired? The resulting emulsion oi metallic so- 2 di in the lubricating base is added to a mixture of about 480 g oi commercial stearic acid and 800 grams of 2000 via. at 100 F. coastal red oil. The reaction is'exceedingly sluggish and is not completed even after cooking for 1 hour. at to present had failed to react with the metallic 40 The above run was repeated utilizing the identical procedure, but instead of using can grams oil stearic acid, there was substituted therefor a mixture of 360 grams of stearic acid and '120 4 grams of IZ-hydroxy stearic acid, In the presence of the lZ-hydroxy stearic acid the saponitication reaction and other gr :1 making reactions proceeded smoothly and rapidly being completed within minutes. this being indicated by the sudden subsidence of foam and the increase in viscosity of the melt.

LI'he resulting grease had the normal properties of a good commercial grease. More specifically, the properties of the grease were as follows:

Penetration at 77 R: After 60 strokes, 244,

I The micro penetration before rolling in a shell-roller-tester was 140; after 4 hours rolling, the micro penetration was 176, all of the penetration figures being expressed in deci-millimeter units.

il'smnple 2 A mixture of 480 grams of tristearin and 800 grams of 2000 viscosity coastal lubricating mineral oil was mixed with 42 grams of metallic-sodium. This amount of metallic sodium is the stoichiometric amount required to neutralize the fatty acid component of the grease batch including the addition agent. Of course. there may be a slight excess up to about 5% of sodium or oi fatty acid. The resulting mixture of oil and glyceride and metallic sodium is emulsified at 320 1". The reaction proceeded very sluggishly'and was The .35..

as apparent by ,the non-subsidence of the foam and the insignificant change in viscosity lot the melt. The so-produced mass was then mixed with about 8000; grams of the same kind of mineral oil and poured and cooled in the usual man ner. The resultlns grease was mushy and noncohei'ent.

The above procedure was repeated employing the conditions set forth, but instead-of employing 480 grams oi the tristearic glyceride there was substituted therefor 380 grams of. tristearic glyceride and 120 grams of tri-12-hydroxy stearic glyceride. The resulting grease was firm, coherent. and had about the same stability as the grease produced in. accordance with Example l.-

Ezample 3 The procedure set forth in Example 2 was followed, but instead of employing 480 grams of tristearic slycerid e; there was substituted therefor a mixture of 3 60 grams of stearic acid and 120 gr or tri-l2- hy stearic glyceride. The resulting grease-was firm and had normal mechemical properties The penetration in decimillimetcr unim-at 77 F., after 60 strokes, was 250 after 180 strokes, 246-; and after 300 strokes,

Example A mixture of 480 grams ct stearic acid, 70 grams of tri-l2-hydroxy stearic glyceride, grams sor bitan monostearate in 700 grams of 2000 vie.- coastal mineral, lubricating oil was reacted with .47 gm of metallic sodium emulsified in 10s grams of 2000 via. mineral lubricating oil while the mixture was heated at about 390 F. The reaction proceeded smoo. The 20 grams of the sorbitan ester repla the function of '70 grams of hydroxy stearic glyceride. After diluting to 7000 grams with lubricating oil the mixture was poured into pans and cooled in the usual mannerto produce a iirm grease. The penetration in deci-milleter units at 27 F. after 80 strokes was 245;

after 180 strokes, 262i and after 300" strokes, 27d.

1 Example 5 Using the same procedure set forth in Example d but replacing the, sorbitan monostearate by 20,

. grams of sorbide-monostearate, a good stable firm grease is obtained which had a penetration at 'l'l emulsion. The resulting grease which had excel-' lent mechanical properties had a penetration at and after 300 strokes, 28%. Example 6 A mixture of 275 grams or steal-1c acid and is grams of polyetluyleneslycol (molecular weishtr 1500) in 600 grams of 2000 via. coastal lubricating oil was. reacted with an oil emulsion containing 22 grams .of metallic sodium. the reaction being eife'oted atabout 320 E. The reaction proceeded smoothly and was completed after 10 minutes. The resulting mass was diluted with lubricating oil to produce 8000 grams. of finished product. Aftercooling a typical light a lubricant was obtained. The penetration at 'l ,1". after strokes was 332, and after300 strokes, '850, all expressed in deci-millimeters.

The above procedure was repeated using a mixnot completed even after minutes of cooking 75 17 I". after 00 strokes of 296; after strokes,

ture of 62 grams of stearic acid, 35 grams of triaccuse 316; and after 300 strokes, 3 18 expressed in deal-'- millimeters.

. Example 7 A mixture of 60 grains of stearic acid, 10 grams of rapeseed oil containing about 10% of hydroxylated esters and 10 grams of 12-hydr'oxy stearic acid, together with 150 grams of oii, was reacted with 7.2 grams ofsodium emulsified in 80 grams of 2000 vis. mineral lubricating oil and the mass heated to 360 F. The reaction proceeded smoothly and rapidly. The mass was diluted with a mineral oil of the same viscosity to produce a final mass of 1000 grams, and thereafter cooled to produce a firm grease with good mechanical properties and showing no tendency to bleed.

It is desired to point out that some materials furnishing i2-hydroxy stearic acid, which may be the acid or an ester thereof, are soluble in the oil component of the lubricating grease and, therefore, require no blending agent for their incorporation in the grease. Other materials furnishing the lg-hydroxy'stearic acid radical may be only slightly soluble or soluble with difficulty in mineral oils, animal oils, and vegetable oils usually used in the manufactured greases; therefore, it

may be necessary to provide a dispersion agent for the same.

The l2-hydroxy stearic acid radical in one form may be provided by hydrogenated ricinoieic acid.

While usually the oil base is a mineral oil base, it is obvious that the mineral oil base may have mixed therewith any of the well known lubricating bases including hydrogenated fish oil, animal oils, vegetable oils and/or rosin. or synthetic ester, or plurality thereof, all as well known in the grease-making art. The oil base may be a vegetable oil base or an animal oil base or a mixture as well known in the art. The term lz-hydroxy stearic acid" is used in accordance with the common usage which means that the hydroxy group is on the twelfth carbon atom from the carboxyl V group.

6 I saponifled. Usually the amount of um used is that stoichiometric amount required exactly neutralize the fatty acid. In some cases a slight der to impart certain-desirable properties to the finished grease.

In carrying out the present invention the saponiflable component of the grease making batch the temperature of the oil being above the melting point of sodium which is 97 C. The molten sodium is agitated in the hot oil by any known means. Preferably the emulsion of molten sodium in the oil is produced by homogenizing which is a well known method of producing emulsions. may be stated that it has been observed that the emulsion reacts best when it has been stirred in the presence of an oxygen-containing atmosphere as, for example, the air, for a suiiicient length of time until the emulsion acquires a binish-gray appearance. While in the herein examples, the emulsionis produced by dispersing the molten sodium in mineral oil, it is obvious that other types of dispersion medium may be used so long as the dispersion medium is substantially chemically inert relative to the molten sodium provided the dispersion medium has a boiling point above the melting point of the sodium. Any hydrocarbon or ether having a boiling point above the melting point of the sodium and chemically inert with respect to the sodium may be used as the dispersion medium. The emulsion can be prepared in a concentration of 1 to 70% of sodium,

the preferred range being between 10% to 30%. The amount of molten sodium used is a function of the amount and molecular weight and basiclty of the fatty acids employed including the addition agent. In other words, the amount of sodium used may be any of the components usually used in the production of grease. The fatty acids usually used in grease making are the saturated'fat'ty acids containing from 14 to 32 carbon atoms and the unsaturated fatty acids containing from 18 to 22 carbon atoms. Instead of using the said fatty acids, the glycerides thereof'may be used as well as the monohydric alcohol esters of certain fatty acids or .the wax esters of said acids.

The addition agent may comprise any of the materials herein set forth including IZ-hydroxy stearic acid. degras which contains hydrox'y palmitlc acid; 9 and/or 10 hydroxy stearic acid,- j the 9, 10 hydroxy stearic acid containing two hydroxy radicals being known as the 9, 10 dihydroxy stearlc acid; blown rapeseed oil; hydrogenated sugars and their stearic and other fatty acid esters. lycols and related compounds.

- In producing grease in accordance with the presentinvention, the grease making batch may be heated to a temperature varying from 200 F.

to 600 F.; however, the preferred heating range varies from about 290 F. to about 400 F.

In forming or producing greasein the presence of metallic sodium, water is not produced by the saponiflcation of the higher fatty acids or the esters. Since no water is formed during the sa-' considerable saving in heat energy required be-- cause of the shorter time cycle in order to produce the grease: therefore, for a given size of grease-making kettle, more grease can be made for each 24-hour period.

Utilizing the metallic sodium and the addition agent of the present invention, the grease-mak ing reaction is completed in a time p riod varying from about 10 to 25 minutes which compares with the usual time period of from about 50 minutes to 90 minutes when using sodium hydroxide instead of metallic sodium. In general, using metallic sodium and the addition agent of the present invention, the time period varies from about one-fifth to one-half of the time period which is necessary to react a batch of equivalent weight when usln-g sodium hydroxide.

The present invention sets forth a method of manufacturing a soap base grease comprising forming a mixture of a lubricating base; which" or any of the materials herein set forth; metallic sodium which acts as a saponifylng agent; and an addition agent having a hydroxy fatty acid component which is intended to be a generic expression to include hydroxy fatty acid. itself, or

' an ester thereof. After forming a grease-making I pleted. It is, of course. to be understood that any depends on the amount of acid material to be of the usual temperatures used in making grease may be used in carrying out the present invention provided the temperature is above the meltmay be used which are set forth in Klemgards:

book entitled: "Lubricating Greases; Their Manufactune and Use" (1937), published by the Reinhold Publishing Company, New York. Usually the saponiflable grease making component is a fatty acidior an ester, but any saponifiable me= dium may be used which has hitherto been used in .the making of grease and saponified by sodium hydroxide or an. equivalent saponiiying agent.

when the addition agent is a hydrouy ietty acid, the amount thereof may vary between 15% and 30% taken on the weight of the saponliiabie grease-making component present in the wwhen the addition agent is a polyhydroxy com pound as, forexample, any of those set forth in Examples 4, and e, the amount of addition agent used may broadly vary from about l% to 25%, but preferably from about 3% to 5% taken on the weight of the saponifiable grease-melding component present in the grease. ierring to Example 8, good results have been obtained using polyethylene glycol as the addition agent, but a somewhat better result is obtained when using a mixture of lil-hydroxy stearic acid and polyethylene glycol, the latter being present in minor proportion as, for example to 35%, the balance being lz-hydroxy stearic acid,

- In practicing the present invention the addition agent when it comprises a higher hydroxy fattyacidester may be present in an ount between 10% and 50% based on the weight of the saponifiable fatty material. en the addition agent comprises the iz-hydroxy tatty acid or the ifi-hydroxy stearic acid. said addition agent may be present in the grease-making batch in an amount varying between 10% and 80% based on the weight of the saponifiable fatty material. Similarly, when using tri-lZ-hydroxy steal-in glyceride, the latter may be present in an amount between 10% and 50% taken on the weight of. the saponifiable fatty materiel. Fun

ther, when using the higher hydroxy iatty acids and esters thereof, in one form of the invention, these materials may be present in a greasemaking batch in an amount varying between and taken on the weight oi the saponifiable grease-making material. I

Greasemede in accordance with, the present invention may be compounded in the cold with other greases. as, for example, calcium soap greases, aluminum stearate greases. and the like. Wherever the term polyalkylene glycol" or theterm polyethylene glycol is used in the present specification, it is intended to cover those glycols having a molecular weight varying from 400 to 6000 The polyalkylene gi'ycols herein referred to are aroduced by the polymerization of alkylene ox- In making a soda base grease, in accordance with the present invention, instead of using sorbitan monostearate as the addition agent whereby the formation of shells of hard reaction product around the sodium particles are inhibited, other sorbitan esters may be used, as for example, sorbitan oie'ate, sorbitan myristate, and sorbitan laur= ate: and in general the oil-soluble fatty acid esters of sorbitan, the fatty acid radicals of which have more than 8 carbon atoms. I

In general, in accordance with the present in vention, there is provided a soda base grease containing 2% to 1.0% of a sorbitan ester of a fatty acid having at least 8 carbon atoms in the fatty acid radical. Preferably, the fatty acid which is combined with the sorbitan radical may have nywhere from a to 29 carbon atoms. It is not Having thus described the invention, what is cled as new and desired to be secured by Letters Patent is:

1. The method oi manufacturing a soda base grease comprising forming a mixture of a lubrieating base, a material furnishing a non-hydrous" saponifiable fatty material, metallic sodium, act ing as a saponifying agent, and an addition agent selected from the group consisting of the higher hydroxy fatty acids and esters thereof: and heat-- ing said mixture until saponiflcation, and the grease'making reaction are substantially com-- pleted.

2. The method of manufacturing a soda base comprisingfor'ming a mixture 02- a lubrleating base, a material furnishing a non-hydrony saponiflable fatty material, metallic sodium, acting as a saponlfying agent, and an addition agent comprising a higher hydroxy fatty acid ester; heating said mixture until saponificatiou, and the grease making reaction are substantially completed. 3. The method of manufacturing a, soda base grease comprising forming a mixture oi a lu-' bricating base, 'a material furnishing a non-hydroxy saponifiable fatty material, metallic sodium, acting as a saponifying agent, and an addition agent comprising a lil-hydroxy fatty acid; and

pieted.

4. The method of manufacturing a soda base grease comprising forming a. mixture of a lubri eating base, a, material furnishing a non-hydroxy saponifiable fatty material, metallic sodium, acting as a saponifying agent, and an addition agent comprising lfl-hydroxy stearic acid: and heating said mixture until saponification, and the grease 1 making reaction are substantially completed.

5. The method of manufacturing a soda base grease comprising forming a mixture of a lubricating base, a material furnishing a non-hydroxy saponiflable fatty material, metallic sodium, actins as a saponifying agent, and an addition agent comprising tri'-12-'hydroxy stearinic glyceride; and heating said mixture until saponiflcation. and tllie-ggease making reaction are substantially com- 1) ete 6. The method of manufacturing a, soda base grease comprising forming a mixture of a lubricating base. a material furnishings. non-hydroxy saponiiiable fatty material, an emulsion of metbllic sodium. and an addition agent selected from the'group consisting of higher hydroxy fatty acids instance and esters thereof which insures the reactions being carried to completion: and cooking said mixture until saponitlcation and the e mahreaction are substantially completed.

7. The method of manufacturing a soda base grease comprising forming a mixture of a lubricating base, a material furnishing a non-hydroxy aaponlflable fatty material, an emulsion of metallic sodium in lubricating oil, and an addition agent selected from the group consisting of the higher hydromr fatty acids and esters thereof which insures the reaction's being carried to completion; and cooking said mixture until saponification and the grease making reaction are substantially completed.

8. The method of manufacturing a soda base greaselcomprislng emulsifying molten sodium in a lubricating oil 'at a temperature above the melting point of the sodium, mixing the emulsion with a lubricating base, a non-hydroxy saponiiicable fatty material, and an addition agent selected from the group consisting of the higher hydroxy fatty acids and esters thereof, and heating the resulting mass until ,saponiflcation and the grease making reaction are substantially completed.

9. The method of manufacturing a soda base grease comprising emulsifying molten sodium in a lubricating oil while the latter is eing agitated in the presence of an oxygen-con phere, said emulsifying being carried out at a temperature above the melting point of the sodlum, mixing the emulsion with a lubricating base, a non-hydroxy saponifiable fatty material and an addition agent selected from the group consisting of the higher hydroxy fatty acids and esters thereof; and heating the resulting mass until saponiflcation and the grease making reaction are substantially completed.

10. The method of manufacturing a soda base ease comprising forming a mixture of a lubricating base, a material furnishing a non-hydroxy saponiflable fatty material, metallic sodium, acting as 'a saponifying agent, and 10 to 50% of an addition agent selected from, the group consisting of the higher hydroxy fatty acids and esters thereof, said percentage being taken on the weight of the saponiilable fatty acid; and heating said mixture until saponiflc'ation, and the grease making reaction are substantially completed.

11. The method of claim 2 wherein the higher hydroxy fatty acid ester is present in an amount varying between 10% to 50% based on the weight of the fatty acid material. I

12. The method of claim 3 wherein the 12-hydroxy fatty acid is present, in an amount varying between 10% to 50% based on the weight of the fatty acid material.

13. The method of claim 4 wherein the 12-hydroxy stearic acid is present in an amount varying between 10% to 50% based on the weight of the fatty acid material.

14. The method of claim wherein the tri-' 12-hydroxy stearinic glyceride is present in an amount varying between to 50% based on the weight of the fatty acid material.

15. The method of claim 1 wherein the addition agent is present in an amount, varying between 15% and taken on the weight-of the saponlilable fatty material.

16. The method of manufacturing a, soda base grease comprising forming a mixture of a lubricating base, a non-hydroxy saponiflable fatty acid material, metallic sodium, acting as a saponii'ying agent, and an addition agent selected from the group consisting of the higher hydroxy fatty acids n8 atmos- I I file of this patent:

. Number and esters thereof; and heating said mixture to a temperature varying between 200 F. and 600 F. until saponidcation. and the grease making reaction are substantially completed.

17. In the methodof manufacture of a sodium base grease from a mixture containing a saponiiiable fatty material and a lubricating base, the step of substantially completely saponifying and neutralizing the fatty material by molten sodium in the presence of an addition agent selected from the group consisting of the higher hydroxy fatty acids and esters thereof, said saponiiying and neutralization step being carried out at a temperature above the melting point of the molten sodium.

I 18, The method of manufacturing a soda base grease comprising forming a mixture of a lubri cating base, a. non-hydroxy saponlfiable fatty material, metallic sodium, and an organic addition agent selected from the group consisting of the higher hydroxy fatty acids and esters thereof which prevents the formation of shells of hard reaction product around the sodium globules on the heating of the sodium above the melting point thereof; and heating said mixture until saponiflcation and the grease-making reaction are substantially completed.

19. The method of manufacturing a soda base grease comprising forming a mixture of a lubricating base, a saponifiable fatty material, metallic sodium, acting as a saponifying agent, and an addition agent comprising a mixture of 12-hydroxy fatty acid and a polyethylene glycol having a molecular weight above 400; and heating said mixture until saponification, and the grease making reaction are substantially completed.

20. The method of manufacturing :a. soda base grease comprising forming a'mixture of a lubrieating base, a saponiflable fatty material, metallic sodium, acting as a saponifying agent, and an addition agent comprising polyethylene glycol having a molecular weight above 400; and heating said mixture until saponification, and the greasemaking reaction are substantially completed.

21. The method of manufacturing a soda base grease comprising forming a mixture of a lubricating base, a non-hydroxy saponifl'able fatty material, metallic sodium, and an organic addition agent which prevents the formation of shells of hard reaction product around the sodium globules on the heating of the sodium above the melting point thereof, said addition product being selected from the group consisting of the higher hy-.

UNITED STATES P ATENTS Name .11 Date Flero May 10, 1942 FOREIGN PA'IE'NTS OTI -IER REFERENCES Number Klemgard, Lubricating Greases, p e 86, pub.

1937 by Reinhold Pub. Corp. of'New York. 

